There is known an optical reception circuit that converts a light signal to an electric signal. An existing optical reception circuit includes a head amplifier, a dummy amplifier, a peak detecting unit, an average value detecting unit, and a differential amplifier. In the existing optical reception circuit, the peak detecting unit detects a peak voltage between the head amplifier and the differential amplifier. Then, the peak detecting unit outputs the peak voltage detected to the average value detecting unit. The average value detecting unit calculates a threshold voltage from the peak voltage received from the peak detecting unit and a voltage received from the dummy amplifier, and outputs the threshold voltage to the differential amplifier.
In this way, the existing optical reception circuit uses the peak detecting unit and the average value detecting unit to generate a threshold voltage for preventing the distortion of an output waveform from the differential amplifier. Examples of prior art documents related to this application include PTL 1.